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[Bug 6235] Restriction from xs:anySimpleType

From: <bugzilla@wiggum.w3.org>
Date: Tue, 25 Nov 2008 01:34:45 +0000
To: www-xml-schema-comments@w3.org
Message-Id: <E1L4mpB-0003rn-LG@farnsworth.w3.org>


C. M. Sperberg-McQueen <cmsmcq@w3.org> changed:

           What    |Removed                     |Added
           Keywords|                            |needsReview

--- Comment #1 from C. M. Sperberg-McQueen <cmsmcq@w3.org>  2008-11-25 01:34:45 ---
I agree that if the type FB is anySimpleType, the result of
constructing a simple type component which restricts FB with a
non-empty set of facets will be a component which violates the rule
given in 3.16.1.

This appears at first glance to be a case of the constraints on XML
being changed to require less knowledge of the entire schema, and the
XML mapping rules being changed to work for all valid schema documents
(including some which used to fail the 'XML constraints' based on
information not present in the XML).  Some cases which used to fail
(notionally) in the XML constraints, which the mapping rules didn't
need to cater for, now fail (notionally) at the time when component
constraints are checked.

For some of these cases, we have added health warnings pointing out
that the mapping rules are not guaranteed to produce legal components.
I think that at the ftf meeting last month the WG was inclined not to
add more health warnings than are already present, but if we decide to
reverse that policy, we could add the following warning after clause 2
in the mapping rule:

    Note: if there is no simple type definition corresponding to the
    <simpleType> among the [children] of <restriction> (and if
    therefore S_B is xs:anySimpleType), and the set of facet
    components specified in the <restriction> elementis non-empty, the
    result will be a simple type definition component which fails to
    obey the constraints on simple type definitions, including for
    example clause 1.3 of Schema Component Constraint: Derivation
    Valid (Restriction, Simple).

I am agnostic about the utility of adding such warnings; they are
handy for those who have not yet unlearned the assumption that the
mapping rules will always produce conforming components, but they do
clutter the text a bit for those who have unlearned that expectation
and who thus don't need the reminder.  (Although, as here, it may be
useful to have a pointer to at least one of the constraints that will
be failed.)

On balance, I am inclined to propose that we resolve this bug by
adding the note given above.

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Received on Tuesday, 25 November 2008 01:34:54 UTC

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